In glass container forming machines, the containers typically are formed in two stages. At a first or blank mold stage, a charge or gob of molten glass is formed into a parison or preform in a blank mold. A neck ring is positioned adjacent to the blank mold, and the container neck finish is formed against the neck ring to final size and geometry. The parison then is transferred by means of the neck ring to a blow mold, in which the container body is formed to final size and geometry. The neck ring typically includes two neck ring bodies that are of cast bronze or cast iron construction. It has been proposed to employ inserts assembled to precast neck ring bodies to obtain desired wear and heat transfer properties in the portions of the neck ring that contact the molten glass and form the container neck finish.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A neck ring for a glass container forming machine, in accordance with one aspect of the present disclosure, includes two neck ring sections each consisting essentially of a neck ring body and an insert on the body. The inserts have opposed surfaces for forming closure attachment features on a container neck finish molded in the neck ring. Each neck ring body is of die-formed powder metal construction and is molded or otherwise set around the associated insert. The inserts preferably form the entire glass-contacting portion of the neck ring. The neck ring bodies preferably are of bronze or steel construction, and the inserts preferably are of nickel, bronze or steel construction. The body and insert preferably are sintered together for a metallurgical bond.
A method of making a neck ring for a glass container forming machine, in accordance with another aspect of the present disclosure, includes the step of near-net-shape forming a pair of neck ring bodies of powder metal construction, preferably bronze or steel construction. A pair of inserts of a powder metal different from the neck ring bodies, such as nickel, bronze or steel can be molded into the neck ring bodies to form the glass-contacting surfaces of the neck ring. Each body and associated insert preferably are sintered together to form a metallurgical bond.